This invention relates to vent termination receptacle with an integral damper.
In the construction of HVAC systems, a central air handler delivers air to the interior of the structure through a main plenum duct, and a series of branch ducts which terminate at a vent termination receptacle which attaches to a vent plate for controlling the discharge of air into the space. With a higher pressure air system, the vent termination receptacle includes a housing which is preferably of greater cross sectional area than the supply duct so that the air leaving the ductwork at the vents expands rapidly as it enters the housing and creates a lower air pressure zone around the vent. This is a practical application of Bernoulli""s theorem and the Venturi effect. One of the problems of higher pressure air systems (commonly known as Hi-Velocity systems) is that conventional damper assemblies such as those described in U.S. Pat. Nos. 4,513,655, 4,628,954, 4,653,725, 5,411,438, 5,806,830, 5,813,430, 5,857,617, 5,921,277, and 6,082,704 will cause air noise.
In the history of these Hi-Velocity style systems, no damper has been truly effective without causing noise.
It is one object of the present invention, therefore, to provide an termination receptacle for an air supply duct which includes an integral damper operable by the user to vary or shut off the air flow through the duct.
According to a first aspect of the invention, therefore, there is provided a termination receptacle for an air supply duct comprising:
a housing having a wall surrounding an axis of the housing;
an inlet pipe arranged for connection to the air supply duct for receiving air therefrom;
the inlet pipe being connected to the wall of the housing generally at right angles to the axis so as to communicate the air from the duct through an opening in the wall into the housing;
the housing having one end closed and an opposed open end such that the air supplied into the housing passes from the housing through the open end;
the housing having a mounting flange member at the open end for attachment of the housing to a mounting surface such that the axis is generally at right angles to the mounting surface;
a damper sleeve member having an open discharge end and an insertion portion extending from the discharge end and arranged for insertion into the open end of the housing for receiving the air therefrom
the wall of the housing defining at least a portion thereof at the opening which is circular cylindrical at least partly surrounding the axis;
the insertion portion of the damper sleeve member being arranged rotate around the axis and being shaped to cooperate with the circular cylindrical portion of the housing to move gradually between a first position in which the opening is fully exposed by the insertion portion allowing passage of air from the inlet through the full area of the opening into the housing and a second position in which the insertion portion fully covers the opening thus closing off flow of air through the opening into the housing such that the insertion portion acts as a damper.
Preferably the vent plate itself forms a part of the combination and is attached to the damper sleeve member or is formed as an integral component with the damper sleeve member so that the damper sleeve member is rotated about the axis by the user rotating the vent plate about the axis.
Thus according to a second aspect of the invention there is provided a termination receptacle for an air supply duct comprising:
a housing having a wall surrounding an axis of the housing;
an inlet pipe arranged for connection to the air supply duct for receiving air therefrom;
the inlet pipe being connected to the wall of the housing-generally at right angles to the axis so as to communicate the air from the duct through an opening in the wall into the housing;
the housing having one end closed and an opposed open end such that the air supplied into the housing passes from the housing through the open end;
the housing having a mounting flange member at the open end for attachment of the housing to a mounting surface such that the axis is generally at right angles to the mounting surface;
a damper sleeve member having an open discharge end and an insertion portion extending from the discharge end and arranged for insertion into the open end of the housing for receiving the air therefrom
a vent plate member;
the vent plate member having a plate portion with a central perforated discharge area which is perforated for the passage of air therethrough and a peripheral surrounding flange;
the vent plate member having a projecting connecting portion extending from the plate portion generally at right angles to the plate portion for connecting the vent plate member to the damper sleeve member at the open end thereof for communication of the air from the housing through the damper sleeve member and through the central perforated discharge area;
the connecting portion and the damper sleeve member being arranged such that the vent plate member is maintained attached thereto with the plate portion generally at right angles to the axis so as to lie parallel to the mounting surface on a side thereof opposite to the mounting flange member;
the connecting portion and the damper sleeve member being arranged such that rotation of the vent plate member about the axis causes common rotation of the damper sleeve member about the axis therewith;
the wall of the housing defining at least a portion thereof at the opening which is circular cylindrical at least partly surrounding the axis;
the insertion portion of the damper sleeve member being arranged rotate around the axis with rotation of the damper sleeve member and being shaped to cooperate with the circular cylindrical portion of the housing to move gradually between a first position in which the opening is fully exposed by the insertion portion allowing passage of air from the inlet through the full area of the opening into the housing and a second position in which the insertion portion fully covers the opening thus closing off flow of air through the opening into the housing such that the insertion portion acts as a damper.
Preferably the insertion portion includes a circular cylindrical wall portion at the circular cylindrical portion of the housing. It is not necessary for either portion to form a complete cylinder surrounding the axis since the cylindrical portions need only extend sufficiently around the axis to allow the movement through roughly ninety degrees between the two positions. The remainder of the portions can then differ from the cylindrical shape so long as they do not interfere with the movement.
Preferably the insertion portion has an outer surface in sliding fit with an inner surface of the circular cylindrical portion of the housing. In this case one or both of the portions in sliding fit is formed of plastics material so as to ensure a close fit and a sealing action.
Preferably the insertion portion is substantially circular cylindrical in shape with a cut out at the opening so that the cut out is provided only at the opening and has side edges parallel to the axis.
Preferably the insertion portion extends substantially to the bottom of the housing.
Preferably the inlet pipe is of smaller cross-sectional area than the housing so as to allow expansion of the air as it enters the housing, although this is not essential to the operation.
Preferably the vent plate member and the damper sleeve member are separate and connected by cooperating elements arranged to allow adjustment of the angular position of the vent member relative to the damper sleeve member. Alternatively the vent plate and sleeve can be integral. Alternatively the vent plate and the sleeve can be separate and the sleeve rotatable independent of the vent plate so that the vent plate remains at a fixed position relative to the mounting surface while the sleeve can be rotated by the user by a suitable lever.
Preferably the damper sleeve member includes an interconnecting element for holding the damper sleeve member in the housing to prevent it from falling out in the event that the housing in installed up side down in a ceiling or in the event that the housing is installed with the axis horizontal.
Preferably the housing has a depth between the flange member and the bottom which is no greater than 3.5 inches thus allowing the housing to be installed in the space between conventional two by four studs. However larger or smaller sizes can also be used and the construction is not in any way size specific.
Preferably the damper sleeve member includes two axially spaced cylindrical portions defining a shoulder therebetween.
Preferably the damper sleeve member includes an outwardly projecting tab on an outer surface thereof for projecting into an annular locating slot on the housing, which acts to hold the sleeve in place and also acts to limit the angular movement of the sleeve around the axis.
Preferably the vent plate member and the damper sleeve member are separate and connected by cooperating elements which comprise longitudinally extending ribs and grooves.
Preferably the insertion portion of the damper sleeve member includes a closed end at the closed end of the housing. In this arrangement, the closed bottom end is preferably shaped to provide a smooth curved guide surface at the opening to guide air from the inlet pipe to turn through ninety degrees to flow axially along the housing.
Since having the ability to shut off vents by the end user is desirable, the configuration is provided in the embodiment as described hereinafter in which the velocity and pressure relationship of the airflow is altered sufficiently to allow for a damper that causes minimal noise and minimal air leakage.
This arrangement as described hereinafter provides a vent termination receptacle with integral damper for the Heating, Ventilation, Air Conditioning (HVAC) Industry, particularly for higher pressure air systems. Normally the vent plate has vanes which are simply straight so as to have no effect on the direction of the air flow. However in some cases it may be desirable to provide directional vanes in which case the vent plate can be installed, by rotating the vent plate relative to the sleeve, with the airflow pointing in any direction needed by the application.
An injection molded plastic, two piece vent boot and damper assembly as described hereinafter provides a simple, effective, and economic solution to this problem. The benefits of a plastic assembly are an inherent sound acoustic property greater than that of metal assemblies, as well as a resistance to mal-forming, moisture, mold, and rust.
Air leakage around vanes or flaps that is minimal with lower air pressure systems, is greatly amplified with Hi-Velocity systems, so a tight fit, easily reproducible assembly, as described hereinafter is provided. To further compound the design problem, it is desirable that the entire assembly is small enough to fit in a standard construction 2xc3x974 stud wall to allow for sidewall discharge of the air.
The housing preferably has a barrel with a diameter larger than that of the branch ductwork causes a change in the pressure to velocity ratio of the airflow, which helps minimize a noise increase easily experienced with higher pressure air terminations. The damper sleeve which snugly turns inside this barrel, allows for a closure of the airflow without the xe2x80x9cwhistlingxe2x80x9d experienced from conventional dampening methods. A matching groove and lip on the two pieces further reduces air leakage while also preventing the damper tube from falling out of place when the assembly is installed in a ceiling pointing downward.